The National Cancer Institute describes lung cancer as cancer that originates in the tissues of the lungs, typically in the cells that line the air passages. There are two different kinds of lung cancer: small cell lung cancer and non-small cell lung cancer, based on the appearance of the cancer cells. Once lung cancer is diagnosed, staging can occur. Staging is a standardized system of describing the spread and extent of the cancer, usually based on a TNM system, or characteristics of the tumor, nodes, and whether there are metastases. For lung cancer, stages range from stage 0, which is noninvasive lung cancer, to Stage IV, or widespread metastatic lung cancer.
Significance
According to the National Cancer Institute, in 2009 in the United States, approximately 219,440 new diagnoses of lung cancer were made, and about 159,390 people died from the disease. Small cell lung cancers make up approximately 10 to 15 percent of lung cancers, with non-small cell making up the rest.
Small Cell Lung Cancer
For small cell lung cancer, physicians typically prefer a two-stage system, as opposed to the TNM system and stage grouping, according to the American Cancer Society. Small cell lung cancers are divided into "limited stage," which means the cancer is in one lung and possibly lymph nodes on that side of the chest, and "extensive stage," which describes when cancer has spread to the other lung or lymph nodes on the opposite side, or distant organs. Stage IV small cell lung cancer would be "extensive stage." When the TNM staging is done for this kind of cancer, stage IV is diagnosed when the cancer is any size and may be in adjacent lymph nodes or tissues. In addition, either the cancer has spread to both lungs, there are cancer cells in the fluid surrounding the lung or cancer cells are found in the fluid surrounding the heart. It may also be diagnosed when cancer has spread to distant organs, regardless of the size of the tumor or lymph node involvement.
Non-Small Cell Lung Cancer
For non-small cell lung cancer, the stage determination can be made in two situations. The first situation encompasses cancer that is any size and may have spread to adjacent tissues, organs or lymph nodes, and either the cancer is also in the other lung or cancer is in the fluid around the lungs or heart. The second situation in which stage IV cancer might be diagnosed is if the cancer has spread to distant organs; the original cancer can be any size and lymph nodes may or may not be cancerous.
Treatment
For stage IV non-small cell lung cancer, the National Cancer Institute lists several treatments, including external radiation therapy to help relieve any symptoms, chemotherapy with or without targeted treatment, internal radiation therapy using an endoscope, or clinical trials. For extensive stage small cell lung cancer, the National Cancer Institute describes possible treatments as including combination chemotherapy with possible radiation to the brain, radiation therapy to areas of metastases to help relieve symptoms and clinical trials.
Time Frame
The five-year survival rate is typically used when discussing survival rates for cancer. This number represents the percentage of people who survive at least five years after their diagnosis. For stage IV small cell lung cancer, the American Cancer Society estimates that the five-year survival rate is approximately 2 percent. For stage IV non-small cell lung cancer, the five-year survival rate is 1 percent.
References
- American Cancer Society: How Is Small Cell Lung Cancer Staged?
- American Cancer Society: How Is Non-Small Cell Lung Cancer Staged?
- National Cancer Institute: Lung Cancer
- American Cancer Society: What Are the Key Statistics for Small Cell Lung Cancer?
- National Cancer Institute: Non-Small Cell Lung Cancer Treatment
